lkml.org 
[lkml]   [2014]   [Feb]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] dma: ste_dma40: don't dereference free:d descriptor
On Thu, Feb 13, 2014 at 10:39:01AM +0100, Linus Walleij wrote:
> It appears that in the DMA40 driver the DMA tasklet will very
> often dereference memory for a descriptor just free:d from the
> DMA40 slab. Nothing happens because no other part of the driver
> has yet had a chance to claim this memory, but it's really
> nasty to dereference free:d memory, so let's check the flag
> before the descriptor is free and store it in a bool variable.
>
> Cc: stable@vger.kernel.org
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Applied, thanks

--
~Vinod
> ---
> drivers/dma/ste_dma40.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/dma/ste_dma40.c b/drivers/dma/ste_dma40.c
> index 00a2de957b23..bf18c786ed40 100644
> --- a/drivers/dma/ste_dma40.c
> +++ b/drivers/dma/ste_dma40.c
> @@ -1641,6 +1641,7 @@ static void dma_tasklet(unsigned long data)
> struct d40_chan *d40c = (struct d40_chan *) data;
> struct d40_desc *d40d;
> unsigned long flags;
> + bool callback_active;
> dma_async_tx_callback callback;
> void *callback_param;
>
> @@ -1668,6 +1669,7 @@ static void dma_tasklet(unsigned long data)
> }
>
> /* Callback to client */
> + callback_active = !!(d40d->txd.flags & DMA_PREP_INTERRUPT);
> callback = d40d->txd.callback;
> callback_param = d40d->txd.callback_param;
>
> @@ -1690,7 +1692,7 @@ static void dma_tasklet(unsigned long data)
>
> spin_unlock_irqrestore(&d40c->lock, flags);
>
> - if (callback && (d40d->txd.flags & DMA_PREP_INTERRUPT))
> + if (callback_active && callback)
> callback(callback_param);
>
> return;
> --
> 1.8.5.3
>

--


\
 
 \ /
  Last update: 2014-02-17 10:01    [W:0.038 / U:0.644 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site